Users enter text. That's how it always has been, because they use keyboard. If format is set to General, Excel tries to make the best guess what is inputted an

Users enter text. That's how it always has been, because they use keyboard. If format is set to General, Excel tries to make the best guess what is inputted and convert it to that value, so things like SUM work. That is very sensible behavior. Your accountant doesn't want to set format and only then enter number. She has a job to do, so just do it for her. Same thing for dates. This guessing algorithm has some edge behavior, but always happens. C# DateTime.TryParse("DEC12") will deduce date is 2012-12-01. Yay? Do you want to keep it as text? Add ' as a first character (it's not considered a part of the string) or format cells to non-General format (e.g. Text) before entering a text.